最新刊期
- 摘要：The effects of defects on the performance of all inorganic perovskite solar cells was studied using a one-dimensional solar cell simulation software SCAPS. It is found that in the device ITO/SnO2/CsPbI3/CuI/Au， the density of the defects at the CuI/CsPbI3 interface and in the CsPbI3 photoactive layer have dramatically influence on the performance of the device. With the increase of the defect density， the open-circuit voltage， short-circuit current， filling factor， and power conversion efficiency of the device all decrease， especially when the defect density exceeds 1015 cm-3. On the contrary， the defects at the CsPbI3/SnO2 interface have almost no effect on device performance. By optimizing the defect density of the device， the thickness and doping concentration of the photoactive layer， a power conversion efficiency higher than 20% can be obtained in the all inorganic perovskite solar cells.关键词：perovskite solar cell;all inorganic;defect;simulation
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发布时间：2023-09-29 - 摘要：Element doping plays an important role in regulating multicolor luminescence of the Carbon dots. However， it is difficult to realize the tunable fluorescence emission of Carbon dots in solid state due to serious aggregation induced quenching effect （AIQ） and complicated preparation process. Herein， a kind of nitrogen and boron elements co-doped solid-state fluorescent carbon dots was synthesized by microwave reaction using Phloroglucinol as carbon source， Boric acid as boron dopant and Urea as nitrogen dopant. With the change of nitrogen and boron elements content， the luminescent color of the obtained solid-state carbon dots undergoes variations from yellow， green to blue. After the characterization， it was found that the doping of nitrogen and boron elements formed different structures and new functional groups on the surface of the Carbon dots， in which the synergistic effect of graphitic nitrogen， N-C and B-O/B-N bonds leds to a blue-shift change of luminescent colors and the increasing fluorescence quantum yields （FLQYs） with the increasing contents of nitrogen and boron dopants in these solid-state Carbon dots. In addition， given that these solid-state Carbon dots materials exhibited excellent multicolor luminescence properties， yellow， green and blue solid-state fluorescent Carbon dots with the best luminescence performance after optimizing fabricated WLED devices with excellent chromaticity indexes. The warm-white light and energy-saving and efficient working characteristics in the some devices indicating that these Carbon dots materials possess potential application in the field of lighting.关键词：solid-state CDotss;N and B co-doping;luminescence regulation;LED
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发布时间：2023-09-27 - 摘要：The carbon quantum dots（CQDs）containing different N， O contents were prepared by using solvothermal reaction， and the CQDs/OSTE composites were obtained quickly through cross-linking and curing the CQDs with the off-stoichiometric thiol-ene （OSTE） polymer via the reaction of “click” chemistry. It is found the fluorescence quantum yield（QY）of O-CQDs and N， O-CQDs were increased to 16.5% and 17.6%， respectively. Compared with their QYs（2.6% and 4.5%）in the liquid environment， the enhancement of about 6 and 4 times was achieved， respectively. By analyzing the changes of microstructure and optical properties of CQDs materials before and after curing， we suggested that the enhanced PL QY might originate mainly from the reduction of the oxygen-related non-radiative recombination center， the suppression of the non-radiative transition probability and the synergistic effect of N and S. Our results provide a convenient and efficient method for solid state transformation， surface functionalization and fluorescence enhancement of CQDs， which will promote the application of CQDs in light-emitting diodes， lasers and Luminescent solar concentrators.关键词：carbon quantum dots;off-stoichiometric thiol-ene polymer;cross-linking enhanced emission;Surface state;the luminescence center related to oxygen
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发布时间：2023-09-18 - 摘要：Due to the existence of aggregation-caused quenching （ACQ） effect， the application of carbon dots （ CDs ） in the solid state field is greatly limited， Herein， a new class of nitrogen / sulfur-doped CDs （G-CDs） with high fluorescence quantum yield （PLQY） and AIE effect are obtained with an eco-friendly， low-cost one-pot solvothermal method， and the structure and properties were analyzed and characterized. G-CDs exhibit blue emission （λ = 400 nm） in organic solvents while after adding water， because of AIE effect， G-CDs in the aggregated state manifested as green emission， and the PLQY of the powder was measured to be 48.6 %. With the increase of water concentration， the aggregation fluorescence emission of G-CDs was red-shifted， which confirmed the AIE characteristics of CDs. Based on the unique emission fluorescence and AIE effect， G-CDs have important potential applications in information encryption， ink printing and luminescent lighting.关键词：carbon dots;ACQ effect;aggregation-induced emission;anti-counterfeiting applications
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发布时间：2023-09-18 - 摘要：With the rapid advancement of high-power LED and laser lighting technology， the research on phosphors is frequently involved with the packaging technology， optical design， modularization， and photothermal integration. For this reason， the material design and fabrication that are based on photometric parameters are getting more and more important. Therefore， a systematic understanding of the definition and characterization principles of relevant photometric parameters can facilitate the design and development of phosphor materials. This work aims to provide a concise introduction to the fundamental concepts of photometry for researchers in phosphor materials. Key parameters including luminous intensity， luminous exitance， luminance， and illuminance were introduced and discussed. Furthermore， the characterization methods and principles that are based on research cases were discussed. Finally， the research strategy based on the photometric parameters is prospected， providing new ideas for future study on phosphors.关键词：phosphors;solid-state lighting;photometry;laser lighting
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发布时间：2023-08-31 - 摘要：The phosphors Sr6Lu2-2xAl4O15：xTb3+ were synthesized through the solid-state reaction technique. The structure， photoluminescence properties and concentration quenching mechanisms were researched. The dependence of photoluminescence intensities on Tb3+ concentration was studied. Upon excitation with UV excitation， when the doping concentration x = 0.01， the strongest peak located around 381 nm， which arise from 5D3-7F6 transition of Tb3+； when the doping concentration x = 0.15， the strongest peak located around 545 nm， which arise from 5D4-7F5 transition of Tb3+. The luminescence color changes from blue to yellowish green by adjusting the doping concentration of Tb3+. The concentration quenching mechanisms of Sr6Lu2-2xAl4O15：xTb3+ were studied. The lifetime， thermal stability and quantum efficiency were measured. The Sr6Lu2-2xAl4O15：xTb3+ phosphor is a novel color-tunable phosphor.关键词：phosphors;photoluminescence;color- tunable;Tb3+ doped
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发布时间：2023-08-31 - 摘要：We present the results of a high-speed direct modulation 850 nm oxide confined vertical cavity surface emitting laser （VCSEL）. Optimize the design of strain InGaAs/AlGaAs quantum wells to achieve high differential gain， and adjust the photon lifetime through surface etching to achieve response flattening. The developed VCSEL with an oxide aperture of about 7 µ m has a flat frequency response， a 3 dB modulation bandwidth of 24 GHz， and a relative noise intensity value of -155 dB/Hz. Without any pre- emphasis and equalization technology， the PAM4 modulation data transmission rate can reach 80 Gb/s.关键词：vertical-cavity surface-emitting laser;high-speed;PAM4 modulation
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发布时间：2023-08-29 - 摘要：The wide bandgap semiconductor ZnO ultraviolet （UV） photodetector has many advantages， such as high stability， low cost， and has important application prospects in fields such as national defense， medical care， and environmental monitoring. In this work， ZnO thin films were fabricated on SiO2 substrate using radio frequency magnetron sputtering. Subsequently， a ZnO UV photodetector with a high-gain metal-semiconductor-metal （MSM） structure was achieved. At a bias voltage of 10 V， the detector exhibited a responsivity of 4.90 A/W and an external quantum efficiency of 1668%. This high gain was attributed to the hole trapping at the semiconductor-metal interface under illumination. Furthermore， the modulation rules andt influence mechanisms of gain effect， applied bias voltage， and depletion layer width on the responsivity of ZnO UV photodetector were thoroughly investigated. This research provides an important reference for the development and performance control of high-performance UV photodetectors.关键词：ZnO;ultraviolet photodetector;responsivity;gain effect;depletion layer
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发布时间：2023-08-21 - 摘要：Deep ultraviolet light-emitting diodes （DUV-LEDs） can physically destroy the structure of viruses and bacteria， thus achieving efficient disinfection. Compared with the mature blue LED process， how to improve the packaging reliability and light output efficiency of DUV-LEDs is still a key problem. In this paper， a semi-inorganic packaging DUV-LEDs was prepared by using substrate preheating method of micro-cured encapsulation adhesive and combining with array dispensation method to bond quartz glass in plated dam copper. The output wavelength of the device is 275 nm and its half-peak width is approximately 11 nm. Quartz-packaged DUV-LEDs have higher light output than traditional devices packaged with transparent materials. DUV-LED devices using the packaging technique presented herein exhibit high air hermeticity in vacuum red ink and helium environments. Moreover， in the accelerated aging test， the light decay rate of this packaged device is less than 20%. Experimental results show that using array dispensing to bond quartz glass under substrate preheating is a packaging method to improve the reliability of DUV-LEDs compared with organic packaging.关键词：DUV-LEDs;reliability;Light output efficiency;Substrate preheating;Array dispensing
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发布时间：2023-08-17 - 摘要：Photothermal therapy （PTT） is in dire need of an accurate， efficient and high-resolution thermometer working in the deep tissues to assist its treatment process. In this paper， the high temperature solid state method is employed to synthesize the BaY2O4： Nd3+ powder， in which the thermally coupled Stark sublevels of Nd3+： 4F3/2 are utilized to measure the temperature based on the fluorescence intensity ratio （FIR） technology. The optimal value of its absolute sensitivity， relative sensitivity and temperature resolution is 0.09% K-1， 0.69% K-1 and 0.05 K， which are superior to majority of the same type thermometers. Moreover， the penetration depth of the present sample in the biological tissues can be reached to 8 mm， benefiting from the fact that its excitation and emission wavelength are all located in the biological windows. Beyond that， the sample owns photothermal conversion ability under the irradiation of 808 nm wavelength. All the findings show the potential of Nd3+ single-doped BaY2O4 in deep-tissue PTT.关键词：rare earth;rare earth;photothermal therapy;optical thermometry;photothermal conversion
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发布时间：2023-08-09 - 摘要：The red-emitting Mn4+-activated fluoride phosphors， 28 kinds in total， with intense zero phonon line （ZPL） emission were reviewed， on aspects of the chemical composition， preparation method， crystal structure and photoluminescence property. Several rules were found： （1） The Mn4+-activated fluoride phosphors with intense ZPL can be classified into four categories based on whether Mn4+ is equivalent with the cation being substituted and whether the substituted cations form octahedral coordination structures in the matrix； （2） Distortion of the ［MnF6］ coordination octahedra after doping is necessary to achieve intense ZPL； （3） For most of the fluoride phosphors with intense ZPL， the Mn4+ doping is heteroequivalent， substituting a cation with 3+ valence state； when the substituted ion is tetravalent and six-coordinated， the crystal structure achieving intense ZPL emission is mainly in trigonal crystal system with space group such as P321 and P-3m1； （4） For most of the fluoride phosphors with intense ZPL， the intensity of ZPL is weaker than that of Stokes ν6 phonon sideband emission （expect for five kinds like Na2TiF6：Mn4+ in which the ZPL is more intense than the ν6 peak）； （5） Their ZPLs are located within 617-628 nm， mainly at 620 nm； （6） The ZPL/ν6 （Stokes） intensity ratio is not only dependent on the chemical composition of the phosphor， but also varies with the preparation method for a specific phosphor.关键词：Mn4+;red-emitting phosphor;zero phonon line;fluoride
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发布时间：2023-08-09 - 摘要：Zero-dimensional （0D） organic-inorganic hybrid metal halides， as an important functional material， have received widespread attention in the fields of lighting， display， and x-ray scintillator for their excellent luminescent properties. In 0D organic-inorganic hybrid metal halides， the polyhedral anions of metal halides are surrounded by organic cations and completely isolated， forming a unique “host-guest” structure. Hence， 0D organic-inorganic hybrid metal halides generally exhibit the intrinsic properties of single metal-halide polyhedrons. However， 0D organic-inorganic hybrid metal halides， as an emerging luminescent material， not only contain significant spatial confinement characteristics， but also have tunable micro interactions. Therefore， different components have a significant impact on their photophysical mechanism. Based on this， this review first introduces the solution synthesis methods， crystal structure characteristics， and photophysical mechanism of 0D organic-inorganic hybrid metal halides， and then analyzes in detail the regulation of the photophysical mechanism and optoelectronic applications of 0D organic-inorganic hybrid metal halides. Finally， we summarize and prospect the future applications and research of 0D organic-inorganic hybrid metal halides.关键词：zero-dimensional metal halides;organic-inorganic hybrid;efficient broadband emission;photophysical properties;optoelectronic applications
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发布时间：2023-08-09 - 摘要：NaGd（MoO4）2：Tb3+ phosphors with different Tb3+ concentrations were prepared by a high-temperature solid-state reaction method. The crystal structure analysis by means of X-ray diffraction （XRD） revealed that the samples prepared wre pure-phased. Fluorescence spectroscopy measurements were utilized to investigate the phosphor's fluorescence quenching， and the results indicated that the fluorescence concentration quenching resulted from exchange interactions between Tb3+ ions， and the Ozawa model held for the fluorescence quenching process. The self-generated quenching model proposed by Auzel was used to analyze the 5D4 level fluorescence dynamics of Tb3+， and it was found that the Auzel model can well explain the concentration dependence of fluorescence lifetime. The dependences of the luminescence intensity and lifetime of the 5D4 level of Tb3+ on the sample temperature were investigated. A method for temperature sensing using the fluorescence lifetime was proposed， and the absolute and relative sensitivities of temperature sensing were analyzed.关键词：solid-state reaction;concentration quenching;fluorescent decay;thermal quenching;temperature sensing
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发布时间：2023-08-09 - 摘要：Resolution is a critical parameter in assessing the performance of a display. The demand for higher resolution displays extends beyond the competitive needs of consumer electronics manufacturers to the urgent requirements of fields such as scientific research， industry， and medicine， which need high-resolution displays to present more precise images. In addition， virtual and augmented reality technologies enable ultra-high-resolution displays to provide richer human-computer interaction experiences. Ultra-high-resolution display technology has gradually become a popular research direction. This article introduces the technical means and solutions for achieving high-resolution displays in various new display technologies based on light-emitting diodes， summarizes the applicable conditions and advantages and disadvantages of each solution， and points out the main challenges facing each technology at this stage. Our team has long been committed to the electroluminescent patterning and high-resolution display research of quantum dot light-emitting diode displays. This article introduces the groundbreaking research results our team has achieved recently.关键词：ultra-high resolution display;micro lighting emitting diodes;organic lighting emitting diodes;quantum dot light emitting diodes
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发布时间：2023-07-26 - 摘要：In recent years， white LED has become the mainstream lighting in the market due to its advantages of energy conservation， environmental protection， and long life-time. High performance red phosphor is an important material for improving the color rendering performance of white LED. Mn4+-activated oxyfluoride red phosphors have become a research hot spot due to their excellent luminescent properties and high stability of oxides. In this paper， a variety of red oxyfluoride phosphors using Mn4+as an activator are reviewed. From the perspective of crystal field theory and thermal quenching mechanism， the relationship between the crystal structure of each phosphor and its luminescent properties is classified and detailed， in order to provide theoretical guidance for improving the luminescent properties of Mn4+activated oxyfluoride phosphors. Finally， the advantages and disadvantages of Mn4+activated oxyfluoride red phosphors and the existing problems in the research are summarized， and the future development trend is prospected.关键词：luminescent material;Mn4+;oxyfluoride;red-emitting phosphor;white LED
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发布时间：2023-07-24 - 摘要：With the development of artificial intelligence， big data， cloud computing， Internet of Things， mobile electronics， and so on， the transmission capacity of the traditional optical fiber communication system carried by the rare earth ion-doped single-core single-mode fiber amplifier has gradually approached the limit of Shannon’s law. It is necessary to develop a new material system to broaden the transmission capacity of the optical fiber communication system. Compared with rare earth ions， quantum dots （QDs） have a wide luminescence bandwidth and tunable wavelength， and the luminescence properties of QDs can be modulated by a variety of chemical means. QDs-doped optical amplifier shows broadband optical gain properties， which has attracted wide attention from academia and industry. In this context， this paper proposes to integrate chemically synthesized PbS/CdS core-shell QDs with low-loss polymer to obtain QDs -doped fiber amplifier （QDFA）， realize tunable wavelength and broadband optical amplification in the near-infrared （NIR） communication band. This paper studies and reveals the factors and mechanisms affecting the continuity of polymer fiber. It proposes to reduce the additional pressure related to surface tension， contraction force during solidifying， the friction force by the inner wall of fiber core， and improve the traction force from the pumping by vacuum pump to obtain continuous optical fiber. By optimizing these factors， we obtained continuous fiber core based on heat curing PDMS and light curing NOA61 and NOA85 UV glue. Consequently， the QDFAs realizes the highest gain of 6.5dB， and gain bandwidth of more than 100nm. The results of this paper will facilitate the development of quantum dot fiber optic devices and broadband optical communication technologies.关键词：quantum dots;polymer optical fiber;broadband optical fiber amplifier
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发布时间：2023-07-24 - 摘要：Three novel linear dimeric luminescent materials， BtCzPPQ， DCPPQ and PZPPQ， were synthesized by linking two quinoline receptors together into an electron acceptor （A） using the Suzuki coupling reaction， and by linking donor groups （D） with different electronic donated moiety. All the three materials have good rigidity， thermal stability （Tg > 220 ℃）， and high photoluminescence quantum yields （PLQYs more than 70%）. The effects of structural factors such as the rigidity of molecules， linear length， and the donor group on the electroluminescence properties of the materials were analyzed by characterizing the orbital distribution， thermal stability， and photophysical properties of the materials.关键词：bisquinoline structures;rigidity;donor;electroluminescence
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发布时间：2023-07-03 - 摘要：Ultraviolet communication has extensive applications in laser radar， tactical communication， internal security communication in aerospace plane and on-chip integrated optical communication. Both of the bandwidth and light output power of the traditional deep ultraviolet communication LED were low， and the manufacturing process was complex， which limited their widespread application in long-distance， high-speed communication， and on-chip integrated optical communication fields. Experiments have shown that the increasing of the light emitting area of single device can improve the light output power， but the device capacitance has a negative effect on the bandwidth. Therefore， an important research direction for ultraviolet communication LEDs in the future is to improve the bandwidth and the optical power density of the devices simultaneously. UVC Micro-LEDs with higher light extraction efficiency， lower time constant， short carrier lifetime， faster modulated rate and higher current density than traditional LED have been widely favored by the scientific and industrial communities. This paper summarizes the UV LED， tespecially UVC Micro-LEDs related research progress， and their applications in optical communication and integration on a chip interconnection. It is found that deepening study on the preparation and performance improvement of UVC Micro-LEDs and their arrays will be one of the best solutions for improving the performance of free space and on-chip integrated ultraviolet communication systems in the future.关键词：ultraviolet optical wireless communication;Micro-LEDs;modulated rate;on-chip integrated optical communication;light extraction efficiency
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发布时间：2023-06-14 - 摘要：In order to overcome the influence of environmental change on fluorescence detection， a ratio fluorescence probe was designed and prepared， and dual-wavelength fluorescence emission was used to effectively eliminate background interference. Using o-phenylenediamine， sodium tetraborate and 1-methyl-3-allyl imidazolium bromide as precursors， a one-step hydrothermal method has been developed to synthesize a ratio fluorescent probe based on carbon dots （L-CDs）， and to achieve a double signal response to heavy metal ions （Cu2+）. L-CDs exhibited fluorescence double emission phenomenon， and showed double emission peaks at 440 nm and 570 nm when the excitation wavelength was 380 nm. The addition of Cu2+ can reduce the fluorescence emission intensity at 440 nm and increase the fluorescence emission peak value at 570 nm. The concentration of Cu2+ in the range of 0.04-0.244 mM showed a good linear correlation with the fluorescence ratio signal （F570/F440）， and the detection limit （LOD） was 0.6 μM. The fluorescence probe can be used for the detection of Cu2+ in actual water samples with the recovery of 99.4 ~ 101.4%.关键词：carbon dots;fluorescence probe;cupper ion;Ratio probe
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发布时间：2023-06-14 -
Recent progress in small-molecule fluorescent probes for in situ imaging and detection of enzyme 增强出版
摘要：Enzyme widely exists in various life activities； some diseases are closely related to abnormal expression of active enzymes. Accurate detection of enzyme expression levels and in situ imaging provide a powerful basis for diagnosis and treatment of related diseases. Up to now， a large number of detection technologies have been developed， among which the fluorescent technology represented by small-molecule fluorescent probes has advantages such as non-invasive， high sensitivity， low detection limit， fast response time and good biocompatibility. It is favored in the detection of biological enzyme. However， as small-molecule fluorescent probes are used for detection， they tend to diffuse at the active sites of enzyme， resulting in poor spatial and temporal resolution of the probes. Therefore， in order to improve the spatial and temporal resolution of imaging detection and reduce background interference and false positives， the design of in situ imaging has been proposed， which has become one of the research focuses of optical imaging. At present， researchers have reported that a variety of small-molecular fluorescent probes have been used in the design of enzyme in situ imaging and achieved remarkable results. This review will introduce the design strategy of small-molecular fluorescent probes for enzyme detection and the research progress in situ imaging， hoping to provide some inspirations for researchers in this field.关键词：in situ imaging;small-molecule fluorescent probes;enzyme;recent progress- 84
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发布时间：2023-06-13
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